Intravenous (IV) therapy is a versatile technique used for the administration of medical fluids to and withdrawal of bodily fluids from patients. IV therapy has been used for various purposes such as the maintenance of fluid and electrolyte balance, the transfusion of blood, the administration of nutritional supplements, chemotherapy, and the administration of drugs and medications. Fluids can be administered intravenously by injection through a hypodermic needle, or intermittently or continuously by infusion using a needle or catheter. The most common intravenous access method utilized by clinicians is the peripheral IV catheter.
A peripheral IV catheter is made of soft, flexible plastic or silicone rubber, generally between fourteen to twenty-four gauge in size. In the conventional venipuncture procedure, a catheter is inserted into a vein in the patient's hand, foot, or the inner aspect of the arm or any vein in the body that will accept an IV catheter. Typical peripheral IV catheters are “over-the needle” catheters where the catheter is coaxially placed over an introducer needle. In order to properly place the catheter into a patient's vein, the sharpened tip of the introducer needle, is used to puncture the skin, tissue, and vein wall to provide a path for placement of the catheter.
Placement of a peripheral IV catheter generally includes preparation of the biological site of the patient. Often a tourniquet is applied proximal to the biological site and a variety of techniques can be used to dilate the patient's vein. While wearing disposable gloves, the clinician cleanses the biological site and a vein is retracted or anchored by placing a thumb over the vein about fifty to seventy-five mm distal to the site. The needle and catheter are introduced into the vein by inserting the bevel of the sharpened tip into the vein at about a twenty to thirty degree angle with the bevel facing up in order to pierce one wall of the vein. The catheter thus rides with the needle through the skin, tissue, and vein wall and into the patient's vein.
Various catheter insertion devices have been developed to provide a needle for catheterization. One such example of this type catheter insertion device is marketed by Smiths Medical ASD, Inc. of St. Paul, Minn., under the TELCO trademark, as described in U.S. Pat. Nos. 7,291,130 and 8,257,322 (depicting an IV catheter insertion device marketed by Smiths Medical ASD, Inc. under the INTUITIV Safety IV Catheters trademark), both of which are incorporated by reference herein. In other cases, the catheter insertion device provides a safety needle assembly that functions to house the sharpened tip of the needle to reduce the likelihood of an inadvertent needle stick. Examples of this type of catheter insertion device are described in U.S. Pat. No. 5,000,740 (depicting an IV catheter insertion device marketed by Smiths Medical ASD, Inc. under the PROTECTIV trademark), U.S. Pat. No. 7,736,342 (depicting an IV catheter insertion device marketed by Smiths Medical ASD, Inc. under the VIAVALVE trademark), both of which are incorporated by reference herein.
To finish placement, the needle and catheter are lowered towards the skin to decrease the entry angle, and the catheter is advanced slightly into the vein. The connection between the catheter and needle is then loosened, so that the catheter can be advanced further into the vein as desired, and the needle can be withdrawn from the catheter. Infusion tubing, which can be connected to the catheter, can then be secured to the insertion site by gauze and adhesive tape.
Catheter insertion devices which attempt to lock the catheter to the catheter insertion device during insertion have been created. However, such devices do not consistently enable a smooth release of the catheter from the needle, particularly in a way that reduces or eliminates the risk of an inadvertent needle stick. Accordingly, the applicants have identified a need for a safety catheter insertion assembly that includes a means for smoothly and passively releasing the catheter from the catheter insertion device upon retraction of the needle to a safe position.